Toshiba VRF Dx coil interface device

TC1: Welded on the gas manifold for monitoring the return gas temperature.

TC2: Installed between the liquid pipe distributor and PMV.

TCJ: Installed at the lowest temperature of the capillary tube.

TA/TF: Installed separately at the uniform airflow of the return air outlet and the supply air outlet.

The sensor installation requires the use of the attached welding storage seat, and the valve body needs to be cooled with a damp cloth during welding to prevent the temperature from exceeding 120 ℃.

2. Electrical wiring and settings

The controller motherboard (MCC-1777) allows key settings through dip switches (SW501-SW507, SW701, SW801):

SW501: Select control type (TA/TF/DDC) and DDC control mode (ladder/linear).

SW701: Switch DI1 safety interlock input to voltage type or non voltage type.

SW801: Set Modbus communication terminal resistance.

Attention should be paid to the separation of strong and weak electricity in wiring. PMV and sensor cables should not be tied to power cables, and the length of PMV cables should not exceed 5 meters.

3. DN code setting and debugging

The service mode can be entered through the wired remote control (RBC-ASCU11) to set key DN codes, such as:

DN11: Set the capacity code (corresponding to HP number) for the DX-COIL interface.

DN4AE: Set the valve kit model.

DN4A0-4A3: Set the threshold for 4-20mA fan linkage control.

Before debugging, an insulation test (≥ 1M Ω) should be conducted, and it should be ensured that the outdoor unit valve is fully opened. The trial operation requires entering the testing mode through the remote control to verify the cold and hot functions.

4、 Fault diagnosis and maintenance

The device has a complete self diagnostic function, and fault information is displayed in the form of inspection codes on the remote control, and historical records can be viewed through service mode. Common inspection codes include:

P10: Safety interlock (DI1) input exception.

L30: External fault (DI2) input activated, such as AHU fan failure.

F-class code: Various temperature sensor faults.

Maintenance personnel can quickly locate problems based on the code and carry out repairs using the troubleshooting process provided in the manual. The device also supports Modbus RTU communication (RS-485), making it easy to integrate into building management systems for remote monitoring and diagnosis.

5、 Safety regulations and professional requirements

The manual emphasizes the importance of job safety throughout, and all installation, maintenance, repair, and relocation work must be carried out by qualified installation or service personnel. Before operation, the power must be cut off and a warning sign must be hung. When working with refrigerants, local regulations must be followed, R410A special tools must be used, and good ventilation must be ensured in the working space to prevent suffocation or the production of toxic gases.